Connector, applicator and method for mechanically connecting hollow structures, in particular small blood vessels

ABSTRACT

The invention relates to a connector, applicator and method for mechanically connecting hollow structures, in particular small blood vessels, in order to make an anastomosis. The connector incorporates various features to create a reliable engagement with the vessel walls to make a good connection thereof. The connector comprises knife members to make an arteriotomy in and punch a hole in one of the vessel walls, comprises an expansion portion to cause a large expansion with a minimum profile, and comprises anvil members to reliably bring the staple-like elements to the joining position.

This application is a divisional of U.S. patent application Ser. No.09/708,617, filed on Nov. 9, 2000.

The present invention relates to a connector and applicator formechanically connecting hollow structures, in particular small bloodvessels, through so called anastomoses. Such means may for example beused when making a bypass past narrowings or occlusions of arteriescaused by arteriosclerosis.

One such connector and applicator are known from WO-A-99/21491 ofapplicants. This document discloses several embodiments of connectorswhich are made up of an annular member and circumferentially spacedjoining means for holding the vessel walls together in order to make thejoint between the vessels. The connectors as disclosed are suitable bothfor end-to-side and side-to-side anastomoses.

The object of the present invention is to further improve the connectorand applicator for making mechanical connections between hollowstructures.

To obtain this object, the present invention provides a connector formechanically connecting hollow structures, in particular small vessels,comprising:

an annular member of deformable material, said member having a centerline and being adapted to be permanently deformed by expansion from afirst size in a starting position in which it is delivered to a desiredanastomoses site, to a second, larger size in a joining position inwhich it connects the hollow structures, and

circumferentially spaced means for joining abutting walls of the hollowstructures together, said means including staple-like elements beingadapted to be permanently deformed from a starting position in which theconnector is delivered to a desired site, to a joining position in whichthey engage the hollow structures to connect them, said staple-likeelements having at least two free ends and being attached to the annularmember between its free ends and being tapered from the annular membertowards their free ends.

This connector according to the invention has various advantages. Theexpandability of the annular member is advantageous because, as aresult, the size of the connector is small during delivery, whereas thesize of the annular member can be adapted to the size of the vessels onthe site of the anastomosis. The staple-like elements are very suitablefor holding together adjacent vessel walls of the vessels to beconnected. Due to the tapering, the predictability of the plasticdeformation, which is required to close the staples, is improved. If thestaples should be curved according to a certain curvature, thedeformation will start at the tips and progress towards the annularmember, which leads to a predictable deformation. The tapering can takevarious forms. The staple-like elements may for example be conically orwedge-shaped towards the free ends. Preferably, the radial thickness ofthe staple-like elements is diminished towards the respective free ends,but also the width may be tapered.

In a preferred embodiment, the staple-like elements are substantiallystraight and parallel to the center line of the annular member. Withthis arrangement, the connector can have a minimum diameter whichfacilitates easy handling during an operation. From this straightstarting position, the staple-like elements can be deformed either to aC-shape to form a perfect or overlapping circle, or to a B-shape or anoverlapping B-shape.

In order to further increase the predictability of the deformation phaseof the staple-like elements, the staple-like elements may be providedwith extreme tips which are preformed into the anticipated curve of thedeformation to the joining position.

It is not necessary that the portions of the staple-like elements oneither side of the point of attachments to the annular member are mirrorshaped. The length, thickness and slope towards the free ends can bevaried to accommodate required bending characteristics or vessel wallthicknesses.

It is preferred to make the connector according to the invention fromone piece of material, preferably metal, for example stainless steel316L or titanium. Connectors which are sufficiently small for use incoronary artery bypass surgery can be manufactured from one piece ofmetal by using a combination of cutting with a lathe and subsequentlyusing laser techniques or electric erosion techniques. In this way, theconnector is made directly in 3D. Alternatively, 2D-techniques likephoto-etching and electroplating can be used to make 2D pieces out ofthin, flat material. These can be converted into 3D, either by forcing a2D shape into 3D, or by bending and welding together the beginning andend of the 2D shape.

An easily expandable annular member is obtained if the annular member ismade up from a continuous elongated piece of material having asinusoidal pattern meandering about a circle line through the annularmember. In this case, the staple-like elements are preferably formed atan apex of the sinusoidal pattern.

In order to increase the maximum size of the annular member in thejoining position, it is preferred to have the main plane of the annularmember at an angle to the center line of the annular member.

Due to this feature, the orifice area of the anastomosis can beincreased without increasing the size of the connector and applicator,which is limited by the diameter of the hollow structures through whichthe applicator is inserted. The above feature results in an ellipticalanastomosis with an increased orifice area as compared to a circularanastomosis, while the size of the applicator can remain unchanged. Incase the main plane of the annular member is at an angle of for example45°, the area is increased by a factor √2=1.41. Practically thestaple-like elements of the connector will remain parallel to the centerline of the applicator and connector.

The present invention also includes an applicator for delivering anddeploying a connector for mechanically connecting hollow structures,comprising:

a shank-like element;

a head formed at a distal end of the shank-like element, said head beingadjustable in such a manner that the annular member and the staple-likeelements of the connector are deformed from the starting position to thejoining position when said adjusting takes place,

said head including an inner member and an outer member which arelongitudinally slidable and include longitudinally opposite anvilformations which are movable to and for upon relative sliding movementsof the inner and outer members in order to deform the staple-likeelements to their joining position;

wherein both the inner and outer members are expandable to deform theconnector to the joining position.

Due to the expandability of both the inner and outer members, it ispossible to minimize the radial dimensions of the applicator. It is nowpossible to make the head of the applicator smaller than the radial sizeof the connector in the joining position, since the outer member of thehead of the applicator is enabled to expand together with the connector.

A simple manner to obtain the expandability of the inner and outermembers is to slit or cut them in axial direction. Preferably, the outermember includes at least first slits and second slits, said first slitsare arranged at an end of the outer member which forms part of the headand extends between the anvil formations, said second slits being spacedfrom said and of the outer member, and alternate with the first slitsand are configured in overlapping arrangement.

Due to this configuration of the slits or cuts, the radial as well asthe tangential stiffness of the delicate material between the slits isincreased. This further assists in diminishing the dimensions of thehead of the applicator.

Another advantageous feature to minimize the radial dimensions of thehead is the feature that the anvil formations, on their sides facingeach other, have curved surfaces dictating the deformation of thestaple-like elements, said curved surfaces being formed to such anextent that they terminate at an angle to the longitudinal axis of thehead which is slightly beyond 90°, for example 91°-120°.

These “low profile” anvil formations make the applicator head as slenderas possible, but nonetheless allow for a predictable bending of thestaple-like elements of the connector.

An alternative applicator according to the invention comprises ashank-like element, and a head formed at a distal end of the shank-likeelement, said head being adjustable in such a manner that the annularmember and the staple-like elements of the connector are deformed fromthe starting position to the joining position when said adjusting takesplace. The head includes an inner member and an outer member which arelongitudinally slidable and include longitudinally opposite anvilformations which are movable to and from upon relative sliding movementsof the inner and outer members in order to deform the staple-likeelements to their joining position. The head further includes anexpansion member comprising wedges adapted to slide underneath theannular member.

In this embodiment of the applicator according to the invention, theexpansion of the annular member of the connector is effected by thewedges of the expansion member which slide underneath the annular memberand thereby urging the annular member outwardly.

One way of enabling the wedges to slide underneath the annular member isto make the expansion member slidable relative to the inner and outermembers, and in this embodiment it is advantageous if the wedges areinterleaved with the anvil formations, since the head of the applicatorcan then be made as small as possible.

In this embodiment of the applicator, the simplest design thereof isobtained if the staple-like elements are first deformed to their joiningposition, whereafter the annular member is expanded by the wedges of theexpansion member. In that case it is not necessary to make the outermember expandable and in a preferred embodiment it is even possible toexpand the annular member of the connector and remove it from the headof the applicator in distal direction over the anvil formations of theinner member in a continued operation.

In another embodiment of the applicator according to the invention, thehead includes not only an anastomosis portion which is adjustable insuch a manner that the annular member and the joining elements of theconnector are deformed from the starting position to the joiningposition when said adjusting takes place, but also a punching portiondistally of the anastomosis portion and including two relatively movableparts configured to cause a punching action on a wall of the hollowstructure and to catch or trap a punched-out part of said wall.

With such applicator it is possible to both cut a hole in the vesselwall in order to enable the applicator to enter the vessel, and toperform the anastomosis with the same instrument. This simplifies theprocedure and reduces time and cost.

The invention further includes a method of delivering and deploying aconnector for mechanically connecting hollow structures. This methodcomprises the steps of:

providing a connector for joining adjacent walls of the hollowstructures,

providing an applicator for said connector, said applicator includingcutting means,

making an arteriotomy in the wall of one of the hollow structures,

inserting the cutting means of the applicator partly into said one ofthe hollow structures through the arteriotomy, so as to cut a hole inthe wall,

advancing the applicator up to a desired position,

deploying the connector by means of the applicator so as to connect thewalls of the hollow structures.

The invention will further be described with reference to the drawingsshowing embodiments of the invention by way of example.

FIG. 1 is a perspective view of an embodiment of the connector accordingto the invention.

FIG. 2 is a view of the connector of FIG. 1 in radial direction.

FIG. 3 is a view of the connector of FIG. 1 in axial direction.

FIG. 4 is a perspective view of an applicator for use with the connectorof FIGS. 1-3, on a smaller scale.

FIG. 5 is a front view of the applicator of FIG. 4.

FIG. 6 is a sectional view of the applicator of FIG. 4, along the planeVI-VI in FIG. 5.

FIG. 7 is an axial view of the outer member of the applicator of FIG. 4,on a larger scale.

FIG. 8 is a sectional view of the outer member of FIG. 7 along the planeVIII-VIII.

FIG. 9 is an axial view of the inner member of the applicator of FIG. 4,on a larger scale.

FIG. 10 is a sectional view of the inner member of FIG. 9, taken alongthe line X-X.

FIG. 11 is a very schematic perspective view of members forming the headof an alternative embodiment of the applicator according to theinvention.

FIG. 12 is a sectional view along the line XII-XII in FIG. 11.

FIGS. 13A-13C are longitudinal sectional views of the applicator head ofFIG. 11, in three different positions during deployment of theconnector.

FIG. 14 is a very schematic side view of an alternative embodiment ofthe connector according to the invention.

FIG. 15 is a very schematic side view of the head of an applicator fordelivering and deploying the connector of FIG. 14.

FIG. 16 is a very schematic, partly cut-away side view of the head of afurther embodiment of an applicator according to the invention.

FIGS. 1-3 show an embodiment of a connector for mechanically connectinghollow structures, in particular small blood vessels, such as coronaryarteries. The connector is specially designed for making a side-to-sideanastomosis but may also be used or adapted to make other connections,for example an end-to-side anastomoses or other joints.

The connector as shown comprises an annular one and a plurality ofjoining means in the form of staple-like elements to spaced around thecircumference of the annular member 1. The annular member andstaple-like elements are preferably formed from one piece of material,preferably metal such as stainless steel 316L or titanium.

The annular member as shown in FIGS. 1-3 comprises a continuouselongated element having a sinusoidal pattern meandering about a circleline through the annular member. The alternating waves 3 and 4 of thepattern have a different wave length in order to accommodate thestaple-like elements 2 which are formed at each wave 4, at the apexthereof. The meandering pattern of the annular member 1 creates theexpandability of the annular member by widening the meanders or waves ofthe pattern thereby increasing the diameter of the annular member 1. Thedeformation of the annular member 1 is plastically, so that the annularmember 1 will retain its shape after expansion.

The configuration of the annular member 1 may vary within a broad range,including the length of the annular member 1. The term annular alsocovers tubular members.

The staple-like elements 2 comprise two staple portions 5, 6 whichextend from the point of attachment to the annular member 1 in oppositedirections. In the embodiment shown, both staple portions 5, 6 arealigned and are substantially each other's mirror image, but it shouldbe kept in mind that that need not be the case. Instead thereof, thelength, thickness and slope towards the free ends of the staple portions5,6 can be varied to accommodate required bending characteristics orvessel wall thicknesses.

As is shown in FIGS. 1-3, in which the connector is shown in itsstarting position in which it is delivered to the anastomosis site, thestaple-like elements are substantially straight and extend parallel tothe center axis of the annular member. The staple portions 5, 6 areslightly tapered towards their free ends, both in radial thickness andin circumferential width. The tapering is on the outer side of thestaple portions 5, 6, whereas the radial inner side of the stapleportions 5, 6 extends parallel to the center axis. The circumferentialsides of the staple portions 5, 6 are inclined relative to a radialplane through the center of the staple portions 5, 6 such that the widthof a staple-like element 2 is smaller on the radial inner side than onthe radial outer side. If desired, the extreme tips of the stapleportions 5, 6 may be preformed into the anticipated curve, to increasethe predictability of the deformation of the staple portions 5, 6. Thewaves 3 may also be slightly tapered, i.e. having a diminishingthickness in axial direction in the same manner as the adjacent stapleportions 5.

FIGS. 4-10 show an embodiment of the applicator according to theinvention. The applicator includes a main body 7, a grip 8 extendingdownwardly therefrom on the rear end, a control lever 9 pivotallyconnected to the front end of the main body 7 and extending downwardly,and a stroke limiter 10 pivotally attached to the lower end of thecontrol lever 9 and slidably connected to the lower end of the grip 8. Apin slot connection 11 between the stroke limiter 10 and the grip 8determines the maximum stroke of the control lever 10. The control armmay be locked in position by locking the stroke limiter 10 to the grip8. The control lever 9 is pivotally connected to an intermediate pivot12 in order to provide a long lever arm 13 and a short lever arm 14. Theend of the short lever arm 14 is pivotally connected to a sliding block15, the sliding motion being guided and limited through a bolt 16.

Attached to the sliding block 15 is an outer tube member 17 and attachedto the main body 7 is an inner tube member 18. The inner and outermembers 17, 18 together form a shank-like element and on the free endthereof a head 20 adapted to accommodate a connector in order to deliverit to the anastomosis site and to deploy it into a joining position.FIGS. 7 and 8/8 a show the outer tube member 17 and FIGS. 9 and 10/10 ashow the inner tube member 18 in more detail. Inside of the inner tubemember is an expansion core connected to an expansion control means 22.

The outer member 17 is provided on its distal end with proximal anvilformations or anvils 23 having a curved surface 24 facing, in aassembled condition, corresponding curved surfaces 25 of distal anvilformations or anvils 26 provided on the distal end of the inner member18. The number of distal and proximal anvils 23, 26 is equal to thenumber of staple-like elements 2 of each connector, in this case 8. Theanvils 23, 26 are distributed around the circumference of the inner andouter members 17, 18 in the same manner as the staple-like elements onthe connector, in this case equally spaced around the circumference. Theinner member 18 is provided with a seat 27, proximal of the anvils 26,to accommodate the connector during delivery and in this startingposition of the applicator and connector, the inner and outer members17, 18 have such relative position that the connector is positionedbetween adjacent anvils 23 and 26 of the inner and outer members 17, 18,with each staple-like element 2 being aligned with respective anvils 23,26.

In order to be able to expand the connector which is seated on the seat27 of the inner member 18, this inner member is slitted with cuts orslits 28 extending from the distal end of the inner member 18 a distancein proximal direction. The length of the slits is such that the tonguesleft between the slits 28 may undergo a sufficient radial deflection toexpand the connector to a sufficient extent. The length of the slits mayfor example be 5-10 times the diameter of the inner member 18. The lumen29 through the inner tube member 18 has a flaired end part 30, in whichthe diameter of the lumen is increased in distal direction, for exampleat an angle of approximately 30°. This end part 30 is adapted toaccommodate the tapered end part of the expansion core 21, so that whenthe expansion core 21 is retracted in proximal direction by theexpansion control means 22, the tapered end part urges the tonguesbetween the slits 28 of the inner tube member 18 outwardly so that theconnector present on the seat 27 is expanded.

As is shown in FIGS. 7 and 8, also the outer tube member 17 is slitted.The outer tube member 18 comprises first slits 31 extending from thedistal end of the outer tube member 17 a distance in proximal direction,and partly overlapping second slits 32 which alternate with the firstslits 31 and extend from a position intermediate the ends of the firstslits 31 to a position proximal of the first slits 31. The total lengthof the first and second slits may for example be 5-10 times the diameterof the outer member 18. Due to this slit arrangement, the radial andtangential strength of the outer member 17 is increased.

The operation of the applicator and connector as shown and describedbefore is as follows.

The shank-like element 19 with a connector positioned on the seat 27 ofthe head 20 is inserted into one of the vessels to be joined and isdelivered to the site where the anastomosis should be accomplished. Thecontrol lever 9 is in the position as shown in FIG. 4. If the head 20and therefore the connector is positioned correctly with respect tovessel walls which are positioned around the connector, the expansioncontrol means 22 is actuated to retract the expansion core 21 so as toexpand the inner member 18 and therefore the annular member 1 of theconnector. Since the outer tube member 17 is also slitted, it ispossible for the outer member 17 to follow the expansion of the innermember. As a result the anvil formations 23 and 26 remain substantiallyin their relative opposite positions, so that, after expansion of theannular member 1 of the connector, it is possible to activate the anvils23, 26 in order to deform the staple-like elements 2 of the connector.

The activation of the anvils 23, 26 is effected by sliding the outertube member 17 in distal direction along the inner member 18 so as tobring the opposite anvils 23, 26 closer to each other thereby engagingthe initially straight staple portions 5, 6 of the staple-like elements2 and upon a further approaching movement of anvils 23, 26 the stapleportions 5, 6 follow the curvature of the curved surfaces 24, 25 of theanvils 23, 26. The curved surfaces 24, 25 are shaped as circularsegments, which extend through approximately 91-120°, and preferably115°, which is sufficient to allow a full deformation of each stapleportion 5, 6. Depending on the lateral and radial curvature of thesurfaces 24, 25, staple portions 5, 6 are deformed either to a C-shapeto form a perfect or overlapping circle, or to a B-shape or anoverlapping B-shape. After both the annular member 1 and the staple-likeelements 2 are deformed into their joining position, the staple portions5, 6 clamp the vessel walls of adjacent vessels between each otherthereby effecting an anastomosis. The expansion core 21 can then bemoved back to the starting position so that both the inner and outermembers are collapsed into their unexpanded condition in which the outerdimensions of the distal anvil formations 26 is smaller than the innerdimension of the anular member 1 of the connector in expanded condition,so that the applicator can be withdrawn from within the annular member 1of the connector so as to be removed from the vessel and the body of thepatient.

FIGS. 11-13 show an alternative embodiment of an applicator according tothe invention, which may be used to deliver and deploy the connector ofFIGS. 1-3. FIGS. 11-13 show a head 120 of the shank-like element of theapplicator, said head being formed by an outer member 117 and an innermember 118. The inner member has a seat 127 and distal anvils 126. Theouter member 17 has proximal anvils 123 between each two adjacent anvils123. There is created a gap 133 of sufficient axial length toaccommodate wedges 134 and provided on the distal end of an expansionmember 135. The expansion member 135 fits slidingly around the outermember 117 such that the wedges are positioned in their respective gap133 between adjacent anvils 23 or distally thereof. The wedges 134extend inwardly from the tube-like expansion member 135 up to the outerdiameter of the inner member 118, so that the extreme tips of the wedges134 engage the outer surface of the inner member 118. The extreme tipsof the wedges 134 are sharp so as to facilitate them to slide underneaththe annular member 1 so as to engage the annular member 1 and upon adistal sliding movement of the expansion member 135 relative to theinner and outer members 117, 118, the annular member 1 of the connector1 is expanded by the wedges 134.

In this embodiment, the deformation of the staple-like elements 2 takeplace before the expansion of the annular member 1, so that the innerand outer members 117, 118 are actuated first in order to close thestaple-like elements 2 (FIG. 13 a-13 b), whereafter the expansion member135 is moved in distal direction so as to expand the annular member 1and urge it over the anvil formations 126 so as to remove the connectorfrom the head 120 of the applicator (FIG. 13 c).

FIG. 14 shows an alternative embodiment of a connector for connectingthe walls of hollow structures, in particular small vessels through ananastomosis. The connector includes an annular member 201 havingstaple-like elements 202. The annular member 201 and staple-likeelements 202 are very similar to those of the embodiment of FIG. 1, withthe exception of one aspect. The connector has a center line C which isin the center of the lumen through the connector. The connector alsoincludes a main plane M which extends through the middle of the annularmember. In this embodiment, the center line C is at an angle to the mainplane M, which is different from 90°. In the present case, the anglewithin the plane of the drawing is circa 45°. The staple-like elements202 extend parallel to the center line C.

The reason for using this embodiment is as follows. The maximum size(orifice area) of the anastomosis is limited by the size of theconnector and applicator, which in turn is limited by the diameter ofthe vessel through which the applicator and connector are inserted. Inorder to increase the orifice area of the anastomosis, the plane ofstapling can be tilted, for example 45°. After expansion to the joiningposition, this results in an elliptical anastomosis with an increasedorifice area (in this case √2=1.41) as compared to a circularanastomosis, whereas the size of the applicator remains unchanged. Thus,it is possible to create bigger anastomoses through a blood vesselhaving a particular size.

In practice, the staple-like elements 202 of the connector will remainparallel to the central axis of the applicator, while the meanderingring will extend at an angle of 45° to a plane which is perpendicular tothe center line C. The meandering waves 203, 204 are, however, withinthe circular cylinder around the center line C.

FIG. 15 shows a head 220 of an applicator to deliver and deploy theconnector according to FIG. 14. As is shown, the position of theproximal and distal anvil formations 223, 226 are adapted to therelative position of the staple-like elements 202.

FIG. 16 shows a further embodiment of an applicator for makinganastomoses. In anastomosis procedures, it is often desirable to punchout a hole in the vessel wall at the site of the anticipatedanastomosis. This is especially the case when doing the proximalanastomosis in CABG (coronary artery bypass grafting) operations, wherefor example a piece of saphenous vein graft has to be connected to theascending aorta, which is a big (30 mm) artery and has a significantwall thickness (2-3 mm). However, on a much more delicate scale,punching out a small hole for the distal anastomosis on the coronaryartery itself could also prove to be advantageous.

The embodiment of the applicator according to FIG. 16 has means to punchout a hole in the vessel wall incorporated in the head thereof. FIG. 16shows that the head of this embodiment includes an anastomosis portion336 and a punching portion 337. This punching portion 337 is positioneddistally of the anastomoses portion 336. The punching portion 337includes two relatively movable parts, a distal part 338 and a proximalpart 339. The distal part 338 is mounted on a core 340 running throughthe head and shank and is adapted to be operated in order to moveaxially with respect to the proximal part 339. On their sides facingeach other, both parts 338 and 339 are provided with cutting means,including a circular knife 341 on the proximal portion 339 and a counteredge 342. The circular knife 341 is sized to accurately slide over thedistal part 338 while performing a cutting action in cooperation withthe edge 342. The distal front of the distal part 338 is rounded foreasy insertion into an arteriotomy. Alternatively, this rounded frontcan be replaced by a knife or a conical shape, ending in a sharp point.This configuration permits creating an arteriotomy, punching out a holeand securing the anastomosis with one instrument and requiring only oneinstrument insertion. To punch the hole this rounded front of the distalpart 338 is inserted into the arteriotomy, subsequently this distal part338 is pulled against the circular knife 341 of the proximal part 339. Acircular piece of vessel wall is then cut out and remains trappedbetween and inside the distal and proximal parts 338, 339 which togetherenclose this vessel wall piece. This entrapment is important since loosetissue fragments can embolize.

Subsequently, the applicator is pushed further inwardly so that theanastomosis portion 336 is brought in line with the vessel walls to bejoined. The expansion mechanism of the anastomosis portion 336 isactivated by further retracting the core 340 and distal part 338 inorder to push the expansion core 321 (formed on the proximal part 339)in proximal direction with respect to the anastomosis portion 336 so asto expand the seat 327 where the connector is positioned. The furtheroperation of the applicator is similar to that of the embodiment ofFIGS. 4-10.

This embodiment has the unique feature of being capable to punch a holeand secure the anastomosis during one instrument insertion. Because itis not necessary to remove the applicator between these twomanipulations, there is very limited blood loss and maximum control.This makes the applicator very suitable for making proximal anastomoseson the aorta in port access CABG.

Alternatively, the punch mechanism could be replaced by a single, linearknife, which makes a linear arteriotomy. The applicator is than advancedthrough this arteriotomy and deforms it to a more circular shape.

From the foregoing it is clear that the present invention provides aconnector, applicator and method for mechanically connecting small bloodvessels and the like in a simple, reliable and efficient manner.

The punch mechanism could also be replaced by a simple, circular knife.A pointed wire with a simple retaining mechanism like a hook, extendingdistally to the circular knife would puncture the vessel wall beforecutting and would hold the piece of vessel wall after cutting to preventit from embolizing in the patient.

The invention is not restricted to the embodiments shown in the drawingand described herein before and can be varied within the scope of theaccompanying claims.

1. A connector for mechanically connecting hollow structures, inparticular small vessels, comprising: an annular member of deformablematerial, said member having a center line and a main plane, and beingadapted to be permanently deformed by expansion from a first size in astarting position in which it is delivered to a desired anastomosissite, to a second, larger size in a joining position in which itconnects the hollow structures, circumferentially spaced means forjoining abutting walls of the hollow structures together, said meansincluding staple-like elements being adapted to be permanently deformedfrom a starting position in which the connector is delivered to adesired site, to a joining position in which they engage the hollowstructures to connect them, said staple-like elements having at leasttwo free ends and being attached to the annular member between its freeends and being tapered from the annular member towards their free ends.2.-39. (canceled)